Electric oil pump

ABSTRACT

An electric oil pump includes a pump housing, a first rotor assembly, a pump shaft, a second rotor assembly, a stator assembly, and a circuit board assembly. The pump housing includes at least a first housing, a second housing, and a third housing. A first cavity is formed between the first housing and the second housing. A second cavity is formed between the second housing and the third housing. The first rotor assembly is accommodated in the first cavity. The second rotor assembly, the stator assembly, and the circuit board assembly are accommodated in the second cavity. The first cavity and the second cavity are isolated by an isolation portion, such that working media provided therein do not communicate with each other.

The present application claims the priority to Chinese Patent Application No. 201710769833.8, titled “ELECTRIC OIL PUMP”, filed with the National Intellectual Property Administration on Aug. 31, 2017, which is incorporated herein by reference in its entirety.

FIELD

The present application relates to the field of vehicles, and in particular to components of a vehicle lubrication system and/or a vehicle cooling system.

BACKGROUND

The automobile industry is developing rapidly. With the automobile performance developing toward safer, more reliable, more stable, fully automated, intelligent and environment-friendly and energy saving, electric oil pumps are widely used in vehicle thermal management systems, and can well meet the market requirements.

The electric oil pump mainly provides power for the vehicle lubrication system and/or the vehicle cooling system. How to design the structure of the electric oil pump to improve the structure and the performance of the electric oil pump is an urgent technical problem to be solved.

SUMMARY

An object of the present application is to provide an electric oil pump.

In order to achieve the above object, the following technical solution is provided according to the present application.

The electric oil pump includes a pump housing, a first rotor assembly, a pump shaft, a second rotor assembly, a stator assembly and a circuit board assembly. The pump housing at least includes a first housing, a second housing and a third housing. The electric oil pump has a pump inner chamber, the pump inner chamber includes a first inner chamber and a second inner chamber, a sidewall forming the first inner chamber includes part of the first housing and part of the second housing, and a sidewall forming the second inner chamber includes part of the second housing and part of the third housing. The first rotor assembly is accommodated in the first inner chamber. The second rotor assembly, the stator assembly and the circuit board assembly are accommodated in the second inner chamber. The electric oil pump includes a partition portion, the partition portion is located between the first housing and the third housing, and the first inner chamber and the second inner chamber are located on two sides of the partition portion. The first inner chamber and the second inner chamber are separated by the partition portion; or the electric oil pump further includes a sealing portion, and the first inner chamber and the second inner chamber are separated by the partition portion and the sealing portion. Since a working medium in the first inner chamber of the electric oil pump is not in communication with a working medium in the second inner chamber, the working medium in the first inner chamber cannot enter the second inner chamber. Thus, the second inner chamber does not need to be additionally provided with other structures to prevent the components in the second inner chamber from corrosion, and the electric oil pump has better sealing performance and a simpler structure, which helps to reduce costs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a first embodiment of an electric oil pump according to the present application;

FIG. 2a is a schematic sectional view of the electric oil pump shown in FIG. 1 taken along one direction;

FIG. 2b is a schematic sectional view of a second embodiment of the electric oil pump according to the present application;

FIG. 2c is a schematic sectional view of a third embodiment of the electric oil pump according to the present application;

FIG. 2d is a schematic sectional view of a fourth embodiment of the electric oil pump according to the present application;

FIG. 3 is a schematic sectional view of the electric oil pump shown in FIG. 1 taken along another direction;

FIG. 4 is a schematic front view of the electric oil pump shown in FIG. 1;

FIG. 5 is a schematic front view of the electric oil pump that is not assembled with the first housing shown in FIG. 1;

FIG. 6 is a schematic perspective view of a first embodiment of the first housing shown in FIG. 1 viewed from one direction;

FIG. 7 is a schematic perspective view of the first embodiment of the first housing shown in FIG. 1 viewed from another direction;

FIG. 8 is a schematic front view of the first housing shown in FIG. 6 viewed from one direction;

FIG. 9 is a schematic front view of the first housing shown in FIG. 6 viewed from another direction;

FIG. 10 is a schematic sectional view of the first housing shown in FIG. 6 taken along one direction;

FIG. 11 is a schematic sectional view of the first housing shown in FIG. 6 taken along another direction;

FIG. 12 is a schematic sectional view of another embodiment of the first housing shown in FIG. 1;

FIG. 13 is a schematic perspective view of a first embodiment of the second housing shown in FIG. 1 or FIG. 2a viewed from one direction;

FIG. 14 is a schematic perspective view of the first embodiment of the second housing shown in FIG. 1 or FIG. 2a viewed from another direction;

FIG. 15 is a schematic sectional view of the second housing shown in FIG. 13;

FIG. 16 is a partially enlarged schematic view of portion B of the second housing shown in FIG. 15;

FIG. 17 is a schematic sectional view of a fifth embodiment of the electric oil pump according to the present application;

FIG. 18 is a schematic sectional view of the second housing shown in FIG. 17;

FIG. 19 is a schematic sectional view of a sixth embodiment of the electric oil pump according to the present application;

FIG. 20 is a schematic perspective view of the third housing shown in FIG. 1 viewed from one direction;

FIG. 21 is a schematic front view of the third housing shown in FIG. 19;

FIG. 22 is a schematic perspective view of the third housing shown in FIG. 1 viewed from another direction;

FIG. 23 is another schematic front view of the third housing shown in FIG. 19;

FIG. 24 is a schematic sectional view of the third housing shown in FIG. 19;

FIG. 25 is a schematic perspective view of the partition plate shown in FIG. 2a to FIG. 3 viewed from one direction;

FIG. 26 is a schematic perspective view of the partition plate shown in FIG. 2a to FIG. 3 viewed from another direction;

FIG. 27 is a schematic front view of the partition plate shown in FIG. 25 or FIG. 26;

FIG. 28 is a schematic sectional view of the partition plate shown in FIG. 25 or FIG. 26;

FIG. 29 is a schematic perspective view of a combination of a mounting bracket and a capacitor shown in FIG. 2a to FIG. 3;

FIG. 30 is a schematic front view of the combination of the mounting bracket and the capacitor shown in FIG. 29;

FIG. 31 is a schematic perspective view of the mounting bracket shown in FIG. 2a to FIG. 3;

FIG. 32 is a schematic front view of the mounting bracket shown in FIG. 31; and

FIG. 33 is a partially enlarged schematic view of portion C of the mounting bracket shown in FIG. 31.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present application is further illustrated hereinafter in conjunction with drawings and specific embodiments.

An electric oil pump can be applied in a vehicle lubrication system and/or a vehicle cooling system to provide circulating power for the working medium in the vehicle lubrication system and/or the vehicle cooling system, and the vehicle lubrication system and/or the vehicle cooling system can provide lubricating oil and/or cooling oil for a transmission system.

Referring to FIG. 1, FIG. 2a and FIG. 3, an electric oil pump 100 includes a pump housing, a second rotor assembly 3, a stator assembly 4, a pump shaft 5, a first rotor assembly 8 and a circuit board assembly 6. The first rotor assembly 8, the second rotor assembly 3 and the circuit board assembly 6 are arranged along an axial direction of the electric oil pump 100, so that the axial arrangement of the electric oil pump 100 can be more compact. Specifically, the second rotor assembly 3 is arranged between the first rotor assembly 8 and the circuit board assembly 6. The electric oil pump has a pump inner chamber. The second rotor assembly 3, the stator assembly 4, the pump shaft 5, the first rotor assembly 8 and the circuit board assembly 6 are accommodated in the pump inner chamber. When the electric oil pump 100 is in operation, the circuit board assembly 6 controls the stator assembly 4 to generate a varying excitation magnetic field by controlling a current passing through the stator assembly 4 to change according to a certain rule, the second rotor assembly 3 rotates under the action of the excitation magnetic field, and the second rotor assembly 3 drives the first rotor assembly 8 to rotate by the pump shaft 5. When the first rotor assembly 8 rotates, the working medium is extruded out of a second flow port, thereby generating the power for flowing.

The pump housing at least includes a first housing, a second housing and a third housing. Specifically, referring to FIG. 2a , in the present embodiment, the pump housing includes a first housing 1, a second housing 2 and a third housing 7. The electric oil pump can form a pump inner chamber, and in the present embodiment, the pump inner chamber includes a first inner chamber 80 and a second inner chamber 90. The working medium can flow through the first inner chamber 80, and the first rotor assembly 8 is arranged in the first inner chamber 80. No working medium flows through the second inner chamber 90. The stator assembly 4, the second rotor assembly 3 and the circuit board assembly 6 are arranged in the second inner chamber 90. A sidewall forming the first inner chamber 80 includes part of the first housing 1 and part of the second housing 20, and a sidewall forming the second inner chamber 90 includes part of the second housing 20 and part of the third housing 7. Referring to FIG. 2a , the electric oil pump 100 includes a partition portion 22. The first inner chamber 80 and the second inner chamber 90 are located on two sides of the partition portion 22, respectively. The electric oil pump 100 further includes a sealing portion 50. The first inner chamber 80 is separated from the second inner chamber 90 by the partition portion 22 and the sealing portion 50, so that the working medium in the first inner chamber 80 is not in communication with the working medium in the second inner chamber 90 through the separation by the partition portion 22 and the sealing portion 50. Such an arrangement completely separates the stator assembly 4 and the circuit board assembly 6 from the working medium, thereby ensuring that the performance of the stator assembly and the circuit board assembly is not affected by the working medium. Structures of the sealing portion 50 and the partition portion 22 are described in detail hereinafter.

Referring to FIG. 1, FIG. 2a and FIG. 3, the first rotor assembly 8 is close to one end of the pump shaft 5, the first rotor assembly 8 is connected with part of the pump shaft 5, the second rotor assembly 3 is close to the other end of the pump shaft 5, and the second rotor assembly 3 is connected with part of the pump shaft 5, so that the second rotor assembly 3 can drive the first rotor assembly 8 to rotate by the pump shaft 5. The circuit board assembly 6 is close to one end of the pump shaft 5 mounted with the second rotor assembly 3. One end of the pump shaft 5 extends into the first inner chamber 80, and the other end of the pump shaft 5 extends into the second inner chamber 90. Specifically, one end of the pump shaft 5 close to the first rotor assembly 8 extends into the first inner chamber 80, and the other end of the pump shaft 5 close to the second rotor assembly 3 extends into the second inner chamber 90.

The electric oil pump includes the partition portion. The first inner chamber and the second inner chamber are located on two sides of the partition portion, respectively. The partition portion is located between the first housing and the second housing. The first rotor assembly and the second rotor assembly are arranged on two sides of the partition portion, and the first inner chamber is separated from the second inner chamber through the partition portion. Four embodiments about the arrangement of the partition portion are described below.

Referring to FIG. 1 and FIG. 2a , FIG. 1 and FIG. 2a are schematic structural views of a first embodiment of the electric oil pump. The structure of the first embodiment of the electric oil pump is described below.

Referring to FIG. 1 and FIG. 2a , in the present embodiment, the pump housing includes the first housing 1, the second housing 2 and the third housing 7. The second housing 2 is closer to the second rotor assembly 3 than the first housing 1, the first housing 1 is detachably connected with the second housing 2, and the second housing 2 is detachably connected with the third housing 7, which facilitates the inspection and maintenance for the components arranged in the chamber compared with non-detachable housing connection. For example, if the connection between the first housing 1 and the second housing 2 is opened, an operation status of the first rotor assembly 8 can be inspected, and the first rotor assembly 8 can be replaced as needed; and if the connection between the second housing 2 and the third housing 7 is opened, an operation status of the circuit board assembly 6 can be inspected, and the circuit board assembly can be maintained and replaced as needed, without destroying other components of the electric oil pump, which helps to reduce costs and improve the maintenance efficiency. Specifically, in the present embodiment, the first housing 1 is detachably connected with the second housing 2 through a first connection portion, and the second housing 2 is detachably connected with the third housing 7 through a second connection portion. The first connection portion and the second connection portion are not arranged in the first inner chamber 80 or the second inner chamber 90. The first connection portion and the second connection portion are described in detail below.

Referring to FIG. 2a and FIG. 15, the second housing 2 includes the partition portion 22. The partition portion 22 can support the first rotor assembly 8. The second housing 2 further includes a main body portion 21, the main body portion 21 extends along an axial direction of the second housing 2, the main body portion 21 is cylindrical, and an inner wall of the main body portion 21 can form at least part of the sidewall of the second inner chamber 90 shown in FIG. 2a . The first housing 1 is detachably connected with the main body portion 21, and the main body portion 21 is detachably connected with the third housing 7 as well. In the present embodiment, the sidewall forming the first inner chamber 80 in FIG. 2a includes part of the first housing 1 and part of the second housing 2, and the sidewall forming the second inner chamber 90 in FIG. 2a includes part of the second housing 2 and part of the third housing 7. In the present embodiment, the partition portion 22 is circumferentially arranged along the inner wall of the main body portion 21, that is, the partition portion 22 is fixed to the main body portion 21. In the present embodiment, the partition portion 22 is integrally formed with the main body portion 21, and the partition portion 22 is arranged substantially perpendicular to the main body portion 21, where the “substantially” refers to that the perpendicularity is within a range of 1 mm. In the present embodiment, the partition portion 22 is arranged at a middle-upper portion of the second housing 2, the second inner chamber 90 is formed between the partition portion 22 and the third housing 7, and the first inner chamber 80 is formed between the first housing 1 and the partition portion 22. Such a structure can ensure the sealing of the connection between the partition portion 22 and the main body portion 21, and can prevent the working medium in the first inner chamber 80 in FIG. 2a from leaking through the connection between the main body portion 21 and the partition portion 22, and the structure is simple.

Referring to FIG. 2b , FIG. 2b is schematic structural view of a second embodiment of the electric oil pump. The structure of the second embodiment of the electric oil pump is described below.

In the second embodiment of the electric oil pump, the electric oil pump further includes a fourth housing, and the second housing includes the partition portion. Specifically, referring to FIG. 2b , an electric oil pump 100 a includes a first housing 1 a, a second housing 2 a, a third housing 7 a and a fourth housing 40 a. The first housing 1 a is detachably connected with the second housing 2 a and the fourth housing 40 a. The third housing 7 a is detachably connected with the fourth housing 40 a. Specifically, the second housing 20 a includes a main body portion 21 a, the first housing 1 a is connected with the main body portion 21 a of the second housing 2 a through screws or bolts, and the main body portion 21 a of the second housing 2 a is connected with the fourth housing 40 a through screws or bolts. An electric oil pump 100 b includes a partition portion 22 a, and the partition portion 22 a is integrally formed with the second housing 2 a. Specifically, the partition portion 22 a is integrally formed with the main body portion of the second housing 20 a. Compared with the first embodiment of the electric oil pump, in the present embodiment, the electric oil pump further includes the fourth housing 40 a, and the structure of the second housing 20 a in the present embodiment is different from the structure of the second housing in the first embodiment of the electric oil pump. The structure of the second housing in the present embodiment is equivalent to dividing the second housing in the first embodiment of the electric oil pump into two components, which is relatively advantageous for saving raw materials during component processing and is further advantageous for reducing material costs during processing.

Referring to FIG. 2c , FIG. 2c is schematic structural view of a third embodiment of the electric oil pump. The structure of the third embodiment of the electric oil pump is described below.

In the third embodiment of the electric oil pump, the partition portion is an individual component. Specifically, referring to FIG. 2c , the electric oil pump 100 b includes a first housing 1 b, a second housing 2 b, a third housing 7 b and a fourth housing 40 b, the first housing 1 b is detachably connected with the second housing 2 b, and the third housing 7 b is detachably connected with the fourth housing 40 b. In the present embodiment, the electric oil pump 100 b further includes a partition portion 22 b, and the partition portion 22 b is arranged between the second housing 2 b and the fourth housing 40 b. In the present embodiment, the partition portion 22 b is detachably connected with the first housing 1 b and the second housing 2 b. The first housing 1 b, the second housing 2 b, the partition portion 22 b and the fourth housing 40 b are detachably connected with each other through screws and bolts. Apparently, in order to ensure the sealing of the connections of the components, sealing rings can be provided at the connections. Compared with the first embodiment of the electric oil pump, in the present embodiment, the partition portion is an individual component, which is advantageous for relatively reducing the processing difficulty of the second housing and saving raw materials during the component processing, and is further advantageous for reducing the material costs during processing.

Referring to FIG. 2d , FIG. 2d is schematic structural view of a fourth embodiment of the electric oil pump. The structure of the fourth embodiment of the electric oil pump is described below.

In the fourth embodiment of the electric oil pump, the electric oil pump further includes a fourth housing, and the fourth housing includes a partition portion. Specifically, referring to FIG. 2d , an electric oil pump 100 c includes a first housing 1 c, a second housing 20 c, a third housing 7 c and a fourth housing 40 c. The first housing 1 c is detachably connected with the second housing 2 c and the fourth housing 40 c, and the third housing 7 c is detachably connected with the fourth housing 40 c. Specifically, the first housing 1 c is connected with the second housing 2 c and the fourth housing 40 c through screws or bolts, and the fourth housing 40 c is connected with the third housing 7 c through screws or bolts. The fourth housing 40 c includes a partition portion 22 c, and the partition portion 22 c can support the first rotor assembly. Compared with the first embodiment of the electric oil pump, the structure of the second housing in the present embodiment is equivalent to dividing the second housing in the first embodiment of the electric oil pump into two components, which is advantageous for saving raw materials during the component processing, and is further advantageous for reducing the material costs during processing.

Referring to FIG. 2a to FIG. 5, in the present embodiment, the electric oil pump 100 includes the first rotor assembly 8. The first rotor assembly 8 includes a first rotor 81 and a second rotor 82, the first rotor 81 includes multiple external teeth, and the second rotor 82 includes multiple internal teeth. Referring to FIG. 5, a hydraulic chamber 801 is formed between the internal teeth of the second rotor 82 and the external teeth of the first rotor 81. In the present embodiment, the second rotor 82 is sleeved on the circumference of the first rotor 81, and part of the internal teeth of the second rotor 82 engage with part of the external teeth of the first rotor 81. Referring to FIG. 1 to FIG. 5, the electric oil pump 100 includes a first flow port 11 and a second flow port 12, the first flow port 11 is used for the inflow of the working medium, and the second flow port 12 is used for the outflow of the working medium. Specifically, the working medium can enter the hydraulic chamber 801 through the first flow port 11, and can leave the hydraulic chamber 801 through the second flow port 12. Since there is a certain eccentric distance between the first rotor 81 and the second 82, when the first rotor 81 rotates, part of the external teeth of the first rotor 81 engage with part of the internal teeth of the second rotor 82, thereby driving the second rotor 82 to rotate. Volume of the hydraulic chamber 801 changes during one cycle of the rotation of the first rotor assembly 8. Specifically, when the first rotor assembly 8 is rotated by a certain angle from a starting point, the volume of the hydraulic chamber 801 is gradually increased to form partial vacuum, and the working medium is sucked from the first flow port 11 into the hydraulic chamber 801. When the first rotor assembly 8 continues rotating, the volume of the hydraulic chamber 801 filled with the working medium is gradually decreased, and the working medium is squeezed, so that the working medium entering the hydraulic chamber 801 is extruded out to the second flow port 12, thereby generating the power for flowing. In the present embodiment, the first inner chamber 80 is in communication with the first flow port 11 and the second flow port 12, and the first inner chamber 80 is not in communication with the second inner chamber 90. Since the first inner chamber of the electric oil pump is not in communication with the second inner chamber, the working medium cannot enter the second inner chamber. Thus, the second inner chamber does not need to be additionally provided with other structures to prevent the components in the second inner chamber from corrosion, and the electric oil pump has better sealing performance and a simpler structure, which helps to reduce costs. In the present embodiment, a first communication cavity is provided between the first flow port 11 and the hydraulic chamber 801, and a second communication cavity is arranged between the second flow port 12 and the hydraulic chamber 801. Such a structure buffers the working medium through the first communication cavity and the second communication cavity, which is advantageous for damping vibration and noise. The specific structure is described below.

Referring to FIG. 1 to FIG. 8, the first housing 1 is detachably connected with the second housing 2 through a first connection portion 123, and the second housing 2 is detachably connected with the third housing 7 through a second connection portion 232. The first connection portion 124 and the second connection portion 234 are not arranged in the first inner chamber 80 or the second inner chamber 90. Specifically, in the present embodiment, the first connection 124 includes first screws 1231 (as shown in FIG. 2a ). Referring to FIG. 6, in order to improve the reliability of the connection, the first housing 1 includes a first flange portion 15. The first flange portion 15 extends along a radial direction of the electric oil pump, the first flange portion 15 is formed with first communication holes 13, and the first communication holes 13 are close to an edge of the first flange portion 15. The second housing 2 is formed with first threaded holes 231, and the first threaded holes 231 are formed along the main body portion 21 of the second housing 2. The first screws 1231 pass through the first communication holes 13 and are mounted from a side close to the first housing 1, and are screwed to the second housing 2. Such an arrangement allows at least part of the first screws 1231 to be disassembled outside the housing, and makes the disassembly of the electric oil pump more convenient, thereby facilitating the maintenance of the first rotor assembly of the electric oil pump. Apparently, the first housing 1 may be connected with the second housing 2 in other ways, for example, some detachable connection ways such as insertion and latching. Referring to FIG. 11, in order to prevent the electric oil pump from interfering with other components when the electric oil pump is mounted on the transmission system, the first communication hole 13 includes a first counterbore 131 and a first through hole 132. A diameter of the first counterbore 131 is greater than a diameter of the first through hole 132, and a depth of the first counterbore 131 is slightly greater than a height of a nut of the first screw 1231, such that a top surface of the first screw 1231 is lower than an upper surface of the first flange portion 15 after the first screw 1231 is mounted, thereby preventing the first screw 1231 from interfering with other components. Apparently, in a case that a first screw avoidance portion is provide in a portion of the transmission system corresponding to the electric oil pump, it is not necessary to provide the first counterbore 131 for the first communication hole 13, and only the first through hole 132 is needed, such that the first communication hole 13 can be allowed to be closer to the radial edge of the first flange portion 15 or a distance between the first communication hole 13 and the edge of the first flange portion 15 can be larger, which facilitates the layout of the first communication hole.

Referring to FIG. 2a , the second housing 2 a is detachably connected with the third housing 7 through the second connection portion 232. Specifically, in the present embodiment, the second connection portion 232 includes second screws 2321. Referring to FIG. 14 and FIG. 19, the third housing 7 is formed with second communication holes 73, the second housing 2 is formed with second threaded holes 241, the second threaded holes 241 are formed along the main body portion 21 of the second housing 2, and the second screws 2321 are mounted from a side close to the third housing 7 and is screwed to the second housing 2. Apparently, the third housing 7 may be formed with the second threaded hole, the second housing 2 may be formed with the second communication hole, and the second screws 2321 may be mounted from a side close to the second housing 2 and may be screwed to the third housing 7. The specific structure can be designed according to requirements of the electric oil pump. Such an arrangement makes the disassembly of the electric oil pump more convenient, thereby facilitating the inspection and maintenance of the components in the electric oil pump such as the circuit board assembly. Apparently, the second housing 2 may be connected with the third housing 7 in other detachable connection ways such as insertion and latching. In order to improve the reliability of the connection between the second housing 2 and the third housing 7 and to simplify the structure, a wall thickness of the third housing 7 at the second communication holes 73 is greater than a wall thickness of the third housing 7 at other portions. Referring to FIG. 13 and FIG. 14, the main body portion 21 of the second housing 2 includes a cylindrical portion 201 and a second flange portion 24. The cylindrical portion 201 forms at least part of the second inner chamber. The second flange portion 24 is formed by the cylindrical portion 201 protruding toward the circumference of the cylindrical portion 201. The second flange portion 24 is formed with the second threaded holes 241, and the wall thickness of the second flange portion 24 at the second threaded holes 241 is greater than the wall thickness of the second flange portion 24 at other portions. Apparently, in order to simplify the structure and reduce the profile dimensions of the electric oil pump, the second housing 2 may not include the second flange portion, and the cylindrical portion 201 may be formed with the second threaded holes 241. To ensure the connection strength, the wall thickness of the cylindrical portion 201 at the second threaded holes is greater than or equal to the wall thickness of the cylindrical portion at other portions.

Referring to FIG. 6 to FIG. 11, FIG. 6 to FIG. 11 are schematic structural views of a first embodiment of the first housing shown in FIG. 2a . In the present embodiment, the first housing 1 includes a first main body portion 14 and the first flange portion 15, and a diameter of the first main body portion 14 is smaller than a diameter of the first flange portion 15. The first housing 1 at least includes two first communication holes 13, and the first communication holes 13 are distributed in an array along a circumference of the first housing 1. In the present embodiment, the first communication holes 13 are formed on the first flange portion 15, and the first communication hole 13 is a counterbore. Specifically, the first communication hole 13 is a cylindrical counterbore. The first communication hole 13 includes the first counterbore 131 and the first through hole 132, where the diameter of the first counterbore 131 is greater than the diameter of the first through hole 132, and the depth of the first counterbore 131 is slightly greater than the height of a nut of the first screw 1231, such that the top surface of the first screw 1231 is lower than the upper surface of the first flange portion 15 after the first screw 1231 is mounted, thereby preventing the first screw 1231 from interfering with other components. Apparently, the first communication hole 13 may be a tapered counterbore or an end face counterbore. Such an arrangement can, on the one hand, ensure that the electric oil pump does not interfere with a mounting portion of a gearbox after the first screw 1231 is mounted, and on the other hand, makes the overall structure of the electric oil pump elegant. A minimum distance between the edge of the first communication hole 13 and an outer circumferential surface of the first flange portion 15 of the first housing 1 is greater than or equal to 1 mm, such that it can be ensured that no gap is formed at the edge while processing the first communication hole 13 and no damage is done to the outer circumferential surface of the first flange portion 15 of the first housing 1. A minimum distance between the edge of the first communication hole 13 and an outer circumferential surface of the first main body portion 14 is greater than or equal to 1 mm, such that no damage is done to the outer circumferential surface of the first main body portion 14 of the first housing 1 while processing the first communication hole 13.

Referring to FIG. 6 to FIG. 11, the first housing 1 is further formed with the first flow port 11, the second flow port 12, the first communication cavity 112 and the second communication cavity 121. Referring to FIG. 2a and FIG. 5, the first communication cavity 112 is arranged between the first flow port 11 and the hydraulic chamber 801, the first communication cavity 112 is in communication with the first flow port 11, the second communication cavity 121 is arranged between the second flow port 12 and the hydraulic chamber 801, and the second communication cavity 121 is in communication with the second flow port 12. The first communication cavity 112 and the second communication cavity 121 are configured to buffer the working medium, which is advantageous for damping vibration and noise. In the present embodiment, the first flow port 11 is formed at the first main body portion 14 of the first housing 1, the first communication cavity 112 is arranged at the first flange portion 15 of the first housing 1, and the first flow port 11 is substantially circular. The “substantially circular” refers to that the roundness is within a range of 1 mm. Apparently, the first flow port 11 may also in other shapes such as an ellipse. Referring to FIG. 9, the first communication cavity 112 is substantially arc-shaped, the first communication cavity 112 includes a head portion 1121 and a tail portion 1122, and a flow sectional area of the first communication cavity 112 gradually increases from the head portion 1121 to the tail portion 1122. In the present embodiment, an inner circumferential surface of the first communication cavity 112 is arc-shaped, and other features such as recess portions or protruding portions may be provided on the inner circumferential surface of the first communication cavity. The first flow port 11 is arranged corresponding to the tail portion 1122, which cooperates with the hydraulic chamber 801 in FIG. 5 to form a certain degree of vacuum at the tail portion 1122, and is advantageous for the suction of the working medium.

The second communication cavity 121 and the first communication cavity 112 are substantially circumferentially distributed in the first housing 1, and a line connecting a center of the first flow port 11 and a center of the second flow port 12 substantially passes through a center of the first housing 1, which is advantageous for taking advantage of the entire circumference of the entire electric oil pump and improving the working pressure of the working medium passing through the electric oil pump.

A flow sectional area at the connection between the second flow port 12 and the second communication cavity 121 is greater than the flow sectional area at other portions of the second communication cavity 121, which allows the working medium entering the second communication cavity 112 from the hydraulic chamber 801 in FIG. 5 to be discharged as soon as possible.

In the present embodiment, a fluid flow direction at the second flow port 12 and a fluid flow direction at the first flow port 11 are both arranged along the axial direction of the electric oil pump, that is, the fluid flow direction at the second flow port 12 and the fluid flow direction at the first flow port 11 are arranged in a same direction of the electric oil pump, and an inflow direction of the working medium is substantially parallel to an outflow direction thereof, such that only one sealing portion is required to be arranged between the electric oil pump and the transmission system and the structure is simple. Apparently, the fluid flow direction at the first flow port may be arranged perpendicular to the fluid flow direction at the second flow port, the second flow port may not be arranged in the first housing 1, but be arranged in the second housing 2, for example, such that the inflow direction of the working medium is arranged perpendicular to or at an angle to the outflow direction thereof, to facilitate the assembly of the electric oil pump and the transmission system or to hang the electric oil pump outside the transmission system.

Referring to FIG. 12, FIG. 12 is a schematic structural view of a second embodiment of the first housing shown in FIG. 2a . Compared with the first embodiment of the first housing, in the present embodiment, a connection hole 13′ of a first housing 1′ is a through hole, which is advantageous for improving the connection strength between the first housing and the second housing.

Referring to FIG. 2a , the electric oil pump 100 includes an outer sealing portion, the outer sealing portion includes a first sealing ring 30 and a second sealing ring 32 sleeved on the outer circumferential surface of the second housing 2, the first sealing ring 30 is close to the first housing 1, and the second sealing ring 32 is close to the third housing 7. Referring to FIG. 15, the first sealing ring 30 is sleeved on a second groove 271 of the second housing 2, and the second sealing ring 32 is sleeved on a third groove 281 of the second housing 2. Referring to FIG. 2, such an arrangement can separate the working medium at the inlet and outlet from a space between the first sealing ring 30 and the second sealing ring 32, such that the two do not affect with each other. Referring to FIG. 2a , in the present embodiment, the electric oil pump further includes a third sealing ring 31. Referring to FIG. 10, the first main body portion 14 is provided with a first groove 141, the third sealing ring 31 is arranged in the first groove 141 of the first housing 1. In a case that the electric oil pump 100 is mounted in a gearbox of a vehicle or in an electric drive unit of a vehicle, such an arrangement is advantageous for isolating the low-pressure working medium on the inlet side from the high-pressure working medium on the outlet side.

Referring to FIG. 13 and FIG. 14, the main body portion 21 includes the cylindrical portion 201 and the second flange portion 24, the cylindrical portion 201 includes a first end portion 23 and a second end portion 27, the second flange portion 24 is integrally formed with the second end portion 27, and the first end portion 23 is arranged away from the second flange portion 24. Specifically, in the present embodiment, the first end portion 23 is formed with the first threaded holes 231, the first threaded holes 231 are distributed in a circumferential array or uniformly distributed, the first communication holes 13 of the first housing 1 are arranged corresponding to the first threaded holes 231 of the second housing 2, and the first housing 1 is connected with the second housing 2 through the first connection portion 123. The second flange portion 24 is formed with the second threaded holes 241, and the second threaded holes 241 are arranged corresponding to the second communication holes 73 of the third housing 7. Referring to FIG. 2a , the second housing 2 is connected with the third housing 7 through the second connection portion 232, wherein the first threaded holes 231 and the second threaded holes 241 are both blind holes. Specifically, the first housing 1 is connected with the second housing 2 through the first screws 1231, the second housing 2 is connected with the third housing 7 through the second screws 2321. In the present embodiment, the second flange portion 24 further includes a first protrusion 242, and the second threaded holes 241 are formed on the first protrusion 242. A thickness of the second flange portion 24 at the first protrusion 242 is greater than the thickness of the second flange portion 24 at other portions, which is advantageous for improving the connection strength without increasing the overall thickness and weight of the second housing 2, and is beneficial to reduce costs. Apparently, in a case that the thickness of the second flange portion 24 of the second housing 2 is thick enough, the second flange portion 24 may not be provided with the first protrusion 242, where the “thick enough” refers to that the thickness of the second flange portion is greater than or equal to 3 mm.

Referring to FIG. 2a and FIG. 15, the partition portion 22 further includes a first support portion 29 and a main body portion 221 of the partition portion, the main body portion 221 of the partition portion can support the first rotor assembly 8, and the first support portion 29 protrudes from the main body portion 221 of the partition portion toward the second inner chamber 90. The first support portion 29 can directly or indirectly support the pump shaft 5. Referring to FIG. 2b to FIG. 2d , according to the arrangement of the partition portion, the first support portion 29 changes correspondingly with the position of the partition portion 22, which will not be further described herein.

Referring to FIG. 15, the second housing 2 is formed with an upper chamber 291 and a lower chamber 292, the upper chamber 291 is separated from the lower chamber 292 through the partition portion 22, and the partition portion 22 is integrally formed with the first support portion 29.

FIG. 15 is a first embodiment of the second housing shown in FIG. 2a . Referring to FIG. 2, the electric oil pump 100 includes a first bearing 60, the pump shaft 5 is supported on the first support portion 29 by the first bearing 60, an inner circumferential surface of the first bearing 60 is in contact with an outer circumferential surface of the pump shaft 5, and an outer circumferential surface of the first bearing 60 is in contact with an inner circumferential surface of the first support portion 29. Specifically, referring to FIG. 15, the first support portion 29 includes a first accommodating portion 290, the first accommodating portion 290 is formed with at least part of a first accommodating cavity, and at least part of an inner circumferential surface of the first accommodating portion 290 surrounds the first accommodating cavity. Referring to FIG. 2a or FIG. 3, the pump shaft 5 passes through the first accommodating cavity, and at least part of the outer circumferential surface of the pump shaft 5 is in a clearance fit with the inner circumferential surface of the first accommodating portion 290; or the first bearing 60 is provided in the first accommodating cavity, referring to FIG. 2a or FIG. 3, the pump shaft 5 passes through the first bearing 60, and the outer circumferential surface of the first bearing 60 is in an interference fit with the inner circumferential surface of the first accommodating portion 290. Specifically, in the present embodiment, the electric oil pump is provided with the first bearing 60, the first bearing 60 is arranged in the first accommodating cavity, and the pump shaft 5 passes through the first bearing 60, such that the first support portion 29 indirectly supports the pump shaft through the first bearing 60.

Referring to FIG. 17, FIG. 17 is a schematic structural view of a fifth embodiment of the electric oil pump. FIG. 18 is the second embodiment of the second housing shown in FIG. 17. Referring to FIG. 17 and FIG. 18, in the present embodiment, the pump shaft 5 is directly supported on a first support portion 29′. Specifically, the first support portion 29′ includes a first accommodating portion 290′, and the first accommodating portion 290′ can form at least part of the first accommodating cavity. In the present embodiment, the first accommodating cavity is in communication with part of the first inner chamber 80, the pump shaft 5 passes through the first accommodating cavity, and at least part of the outer circumferential surface of the pump shaft 5 is in a clearance fit with the inner circumferential surface of the first accommodating portion 290′. The inner circumferential surface of the first support portion 29′ is provided with a lubrication groove 298, which is helpful to lubricate the pump shaft and thereby facilitates the rotation of the pump shaft. Compared with the first embodiment of the electric oil pump, in the present embodiment, the first support portion 29 can directly support the pump shaft by the tolerance fit between the first accommodating portion 290′ and the pump shaft 5 without additionally providing the first bearing, thereby making the structure of the electric oil pump more compact.

Referring to FIG. 15, the partition portion 22 is provided with a communication hole 2933, and the communication hole 2933 communicates the upper chamber 291 with the lower chamber 292. Referring to FIG. 2a , the pump shaft 5 extends into the upper chamber 291 through the communication hole 2933.

The first inner chamber 80 is isolated from the second inner chamber 90. There are two embodiments about the isolation arrangement herein. In the first embodiment, referring to FIG. 2a , the electric oil pump 100 includes the sealing portion, at least part of the sealing portion is supported by the first support portion 29, the working medium in the first inner chamber 80 is not in communication with the working medium in the second inner chamber 90 due to the sealing portion 50 and the partition portion 22. Specifically, referring to FIG. 15, the first support portion 29 includes a second accommodating portion 296, the second accommodating portion 296 is formed with at least part of a second accommodating cavity, and at least part of the inner circumferential surface of the second accommodating portion 296 surrounds the second accommodating cavity. Referring to FIG. 2a , the sealing portion 50 includes an oil seal, and the oil seal is provided in the second accommodating cavity. The pump shaft 5 shown in FIG. 2 passes through the oil seal, and the inner circumferential surface of the oil seal is in contact with at least part of the outer circumferential surface of the pump shaft 5. The outer circumferential surface of the oil seal 50 is sealingly fitted to the inner circumferential surface of the second accommodating portion 296, which can prevent the working medium in the first inner chamber from flowing into the second inner chamber and can thereby avoid damage to the circuit board assembly in the second inner chamber.

In the second embodiment, referring to FIG. 19, FIG. 19 is a schematic structural view of a sixth embodiment of the electric oil pump. Referring to FIG. 15, the pump shaft 5 passes through the second accommodating portion 296 in FIG. 15. A clearance is formed between the inner circumferential surface of the second accommodating portion 296 and at least part of the outer circumferential surface of the pump shaft 5, and the clearance is small enough that the working medium in the first inner chamber 80 cannot flow through. The clearance can prevent the working medium in the first inner chamber 80 in FIG. 2 from entering the second inner chamber 90 in FIG. 2a through the clearance. The specific size of the clearance is determined by parameters such as the roughness of the outer circumferential surface of the pump shaft 5, the roughness of the inner circumferential surface of the second accommodating portion and the viscosity of the oil. In the second embodiment, the working medium in the first inner chamber is not in communication with the working medium in the second inner chamber by the arrangement of the clearance.

Referring to FIG. 2a , the electric oil pump 100 further includes a second support portion 91. The pump shaft 5 can be directly or indirectly supported on the second support portion 91. The first support portion 29 and the second support portion 91 are coaxially arranged, which is advantageous for improving the stability of supporting the pump shaft 5.

Referring to FIG. 2a , the electric oil pump 100 further includes a partition plate 9. The partition plate 9 is arranged in the second inner chamber 90, the second support portion 91 is integrally formed with the partition plate 9, and the second support portion 91 is arranged protruding from the partition plate 9 toward the second inner chamber 90. The structure of the second support portion 91 is described in detail below.

The second support portion 91 can directly or indirectly provide support for the pump shaft 5. Referring to FIG. 25 to FIG. 28, the partition plate 9 includes a third accommodating portion 911, the third accommodating portion 911 is formed with at least part of a third accommodating cavity, and at least part of an inner circumferential surface of the third accommodating portion 911 surrounds the third accommodating cavity. There are two embodiments. In the first embodiment, referring to FIG. 2a , the electric oil pump includes a second bearing 70, the second bearing 70 is provided in the third accommodating cavity, and the pump shaft 5 in FIG. 2a passes through the second bearing 70. Specifically, the inner circumferential surface of the second bearing 70 is in contact with at least part of the outer circumferential surface of the pump shaft 5, and an outer circumferential surface of the second bearing 70 is in an interference fit with the inner circumferential surface of the third accommodating portion 911, such that the first support portion 29 indirectly provides support for the pump shaft through the second bearing 70. In the second embodiment, the pump shaft 5 in FIG. 2a passes through the third accommodating cavity, and at least part of the outer circumferential surface of the pump shaft 5 in FIG. 2a is in a clearance fit with the inner circumferential surface of the third accommodating portion 911, such that the second support portion 91 can directly provide support for the pump shaft by the tolerance fit between the third accommodating portion 911 and the pump shaft 5 in FIG. 2a without additionally providing the second bearing, thereby making the structure of the electric oil pump more compact. Referring to FIG. 2a , the first bearing 60 and the second bearing 70 can be rolling bearings or sliding bearings. For medium and low speeds, the electric oil pump with the sliding bearing can meet the requirements of wear and rotation accuracy while reducing the cost. For high-speed electronic oil pumps, wear, rotation accuracy and bearing capacity are key factors in bearing selection. In such cases, rolling bearings will be preferred.

Referring to FIG. 25 to FIG. 28, the partition plate 9 includes the second support portion 91, a first bottom portion 92, a first annular protrusion 94 and reinforcing ribs 93. The reinforcing ribs 93 are distributed in the circumferential array or uniformly distributed. Specifically, the reinforcing ribs 93 connect the second support portion 91 with the first bottom portion 92. Such an arrangement can ensure the mechanical strength of the second support portion 91, such that the second support portion 91 is less likely to be deformed. In the present embodiment, the reinforcing rib 91 has a substantially triangular shape. Apparently, the reinforcing rib may also have other shapes such as rectangular or trapezoidal. Compared with the second support portion 91, the first annular protrusion 94 is arranged closer to the outer edge of the partition plate 9. A diameter of an outer wall of the first annular protrusion 94 is greater than that of the second support portion 91. Referring to FIG. 2a or FIG. 3, in the present embodiment, the partition plate 9 is fixedly connected with the second housing 2. Specifically, referring to FIG. 33 and FIG. 15, the first annular protrusion 94 is in an interference fit with the inner circumferential surface of the cylindrical portion of the second housing 2. Apparently, the partition plate 9 may be connected with the second housing 2 by screws or bolts or by riveting. An outer circumferential surface of the first bottom portion 92 of the partition plate 9 is in an interference fit with the second housing 2. Referring to FIG. 26 to FIG. 28, the partition plate 9 further includes at least two third annular protrusions 95, and the third annular protrusions 95 axially extend in a direction away from the second support portion 91. Specifically, in the present embodiment, the partition plate 9 includes three third annular protrusions 95, and the third annular protrusions 95 are substantially distributed in the circumferential array or uniformly distributed. A threaded hole 951 is arranged at a center of each third annular protrusion 95, which facilitates the fixation and installation of the subsequent components such as a mounting bracket 10 in FIG. 2 a.

Referring to FIG. 15 and FIG. 16, the second housing 2 further includes a first stepped portion 294. The first stepped portion 294 includes a first position-limiting surface 2941 and a second position-limiting surface 2942. The first stepped portion 294 is arranged in the lower chamber 292 of the second housing 2, and the first stepped portion 294 can serve as a position-limit for the stator assembly 4 in FIG. 2a in the axial direction of the electric oil pump. Referring to FIG. 15 and FIG. 16, the second housing 2 further includes a second stepped portion 295. The second stepped portion 295 includes a third position-limiting surface 2951 and a fourth position-limiting surface 2952, and the second stepped portion 295 is closer to the second flange portion 24 of the second housing 2 than the first stepped portion 294. The stator assembly 4 in FIG. 2a is in an interference fit with the second housing 2. Specifically, an outer wall of the stator assembly 4 is in an interference fit with at least part of the second position-limiting surface 2942 of the first stepped portion 294 of the second housing 2. The first position-limiting surface 2941 of the first stepped portion 294 abuts against the stator assembly 4, thereby realizing the position-limiting of the stator assembly 4 in FIG. 1 by the first stepped portion 294 in the axial direction of the electric oil pump and facilitating the position-limiting of the stator assembly.

Referring to FIG. 20 to FIG. 24, the third housing 7 includes a main body 71 and a connection portion 72. Taking the main body 71 as a reference surface, the connection portion 72 is located below the main body 71. The third housing 7 is formed with the second communication holes 73, the second communication holes 73 are arranged corresponding to the second threaded holes 241 of the second housing 2 in FIG. 14. In the present embodiment, the second housing 2 is connected with the third housing 7 through the second screws 2321 in FIG. 2a . Apparently, the two may also be connected with each other by other connection ways such as insertion, latching or welding. Referring to FIG. 24, the connection portion 72 includes a position-limiting portion 76, and a height H2 of the position-limiting portion 76 is substantially equal to a height H1 of a position-limiting portion 243 of the second housing 2 in FIG. 15 where the “substantially equal” refers to that an absolute value of the height difference is within 0.3 mm. Such an arrangement can ensure that contact faces of the third housing 7 and the second housing 2 are as close as possible, and the third housing 7 does not incline during the assembly process, thereby avoiding affecting the insertion between the socket and the connector. The third housing 7 is further formed with mounting holes 77, and the mounting holes 77 are configured to connect with the gearbox or the drive unit. Two mounting holes 77 are provided in the present embodiment.

Referring to FIG. 20 to FIG. 24, the third housing 7 is further formed with protruding ribs 74, the protruding ribs 74 are integrally formed with the third housing 7, and the protruding ribs 74 protrude toward a direction away from the second housing 2. In the present embodiment, the protruding ribs 74 are arranged on the third housing 7 as much as possible to increase a heat dissipation area, which facilitates the heat dissipation of the circuit board. In the present embodiment, the shape of a transverse section of the protruding rib 74 is rectangular. Apparently, the transverse section may also be in other shapes such as trapezoid, triangle, and arc-shaped.

Referring to FIG. 2a and FIG. 29 to FIG. 33, the circuit board assembly 6 includes a circuit board 61, electronic components and the mounting bracket 10. The mounting bracket 10 is arranged between the circuit board 61 and the partition plate 9. The mounting bracket 10 is fixedly connected with the partition plate 9. Specifically, the mounting bracket 10 is connected with the partition plate 9 by screws and bolts. Apparently, the mounting bracket 10 may also be connected with the partition plate 9 by other connection ways such as riveting. The mounting bracket 10 is electrically connected with the circuit board 61, and the mounting bracket 10 can support large-volume electronic components. Referring to FIG. 29 to FIG. 33, the mounting bracket 10 includes an accommodating portion 102. The accommodating portion 102 is integrally formed with the mounting bracket 10 by injection molding. The accommodating portion 102 includes a bottom supporting portion 1021 and a side portion 1022, the bottom supporting portion 1021 and the side portion 1022 form the accommodating cavity. In the present embodiment, the accommodating cavity is provided with a large-volume electronic component, and the large-volume electronic component is a capacitor 101. In the present embodiment, the bottom supporting portion 1021 is substantially arc-shaped, the bottom supporting portion 1021 is in contact with part of an outer circumferential surface of the capacitor 101, and the bottom supporting portion 1021 and the side portion 1022 are provided to facilitate circumferential positioning of the capacitor 101, thereby ensuring that the capacitor 101 do not move circumferentially. The mounting bracket 10 further includes as least two latching portions 103. In the present embodiment, the mounting bracket includes two latching portions 103, and the two latching portions 103 are arranged two sides of the capacitor 101. The latching portion 103 includes a first surface 1031. During the process of mounting the capacitor 101 into the accommodating portion 102, the capacitor 101 come into contact with the first surface 1031 of the latching portion 103 first, and at this time, the first inclined surface 1031 is tangent to the outer circumferential surface of the capacitor 101. When the capacitor 101 is further mounted into the accommodating portion 102, there will be a component force acting on the first surface 1031, so that the latching portion 103 is opened outward. When the part of the outer circumferential surface of the capacitor 101 is in contact with the bottom supporting portion 1021, no acting force is generated between the part of the outer circumferential surface of the capacitor 101 and the first surface of the latching portion 103, and at this time, the latching portion 103 which was originally in the open state is restored to its initial position. On the one hand, such an arrangement can ensure that the large capacitor does not move in a vertical direction, and on the other hand, it will make the disassembly and assembly of the large capacitor simpler, thereby improving the disassembly and assembly efficiency of the large capacitor. The mounting bracket 10 further includes at least two through holes 104, and the through holes 104 are substantially distributed in the circumferential array or uniformly distributed. In the present embodiment, the number of the through holes 104 is substantially equal to the number of the threaded holes 951 of the third annular protrusions 95 of the partition plate 9. Specifically, the mounting bracket 10 includes three through holes 104, and the number of the through holes 104 is equal to the number of the threaded holes 951 of the third annular protrusions 95 of the partition plate 9.

It should be understood that the above embodiments are only intended to illustrate the present application and not to limit the technical solutions described in the present application. Although the present specification has been described in detail with reference to the embodiments described above, it should be understood by those skilled in the art that, various modifications and equivalents can be made to the technical solutions of the present application without departing from the spirit and scope of the present application, all of which should be contained within the scope of the claims of the present application. 

1. An electric oil pump, comprising: a pump housing, a first rotor assembly, a pump shaft, a second rotor assembly, a stator assembly and a circuit board assembly, wherein the pump housing at least comprises a first housing, a second housing and a third housing, the electric oil pump has a pump inner chamber, the pump inner chamber comprises a first inner chamber and a second inner chamber, a sidewall forming the first inner chamber comprises part of the first housing and part of the second housing, a sidewall forming the second inner chamber comprises part of the third housing, and the third housing is configured to shield the circuit board assembly; the first rotor assembly is accommodated in the first inner chamber, and the second rotor assembly, the stator assembly and the circuit board assembly are accommodated in the second inner chamber; the electric oil pump comprises a partition portion, the partition portion is arranged between the first housing and the third housing, and the first inner chamber and the second inner chamber are located on two sides of the partition portion; and the first inner chamber is isolated from the second inner chamber by the partition portion, or the electric oil pump further comprises a sealing portion, and the first inner chamber is isolated from the second inner chamber by the partition portion and the sealing portion.
 2. The electric oil pump according to claim 1, wherein the second housing is detachably connected with the first housing, the second housing is closer to the second rotor assembly than the first housing, the second housing comprises the partition portion, and the partition portion is configured to support the first rotor assembly.
 3. The electric oil pump according to claim 1, wherein the second housing is detachably connected with the first housing, the second housing is closer to the second rotor assembly than the first housing, the partition portion is detachably connected with the first housing and the second housing, the partition portion is configured to support the first rotor assembly, and the partition portion is closer to the second rotor assembly than the second housing.
 4. The electric oil pump according to claim 1, further comprising a fourth housing, wherein the fourth housing is detachably connected with the second housing, the fourth housing is detachably connected with the third housing, the fourth housing comprises the partition portion, and the partition portion is configured to support the first rotor assembly.
 5. The electric oil pump according to claim 1, wherein the partition portion comprises a first support portion, the first support portion is arranged protruding from a main body portion of the partition portion toward the second inner chamber, and the pump shaft is directly or indirectly supported on the first support portion.
 6. The electric oil pump according to claim 5, wherein the first support portion comprises a first accommodating portion, the first accommodating portion is formed with at least part of a first accommodating cavity, the first accommodating cavity is surrounded by at least part of an inner circumferential surface of the first accommodating portion, and the pump shaft passes through the first accommodating cavity, and at least part of an outer circumferential surface of the pump shaft is in a clearance fit with the inner circumferential surface of the first accommodating portion; or the electric oil pump comprises a first bearing, the first bearing is provided in the first accommodating cavity, the pump shaft passes through the first bearing, and an outer circumferential surface of the first bearing is in an interference fit with the inner circumferential surface of the first accommodating portion.
 7. The electric oil pump according to claim 6, wherein the first support portion comprises a second accommodating portion, the second accommodating portion is formed with at least part of a second accommodating cavity, the second accommodating cavity is surrounded by at least part of an inner circumferential surface of the second accommodating portion, the sealing portion comprises an oil seal, the oil seal is provided in the second accommodating cavity, the pump shaft passes through the oil seal, and an outer circumferential surface of the oil seal is sealingly fitted to the second accommodating portion.
 8. The electric oil pump according to claim 6, wherein the first support portion comprises a second accommodating portion, at least part of the pump shaft passes through the second accommodating portion; and a clearance is formed between the inner circumferential surface of the second accommodating portion and at least part of the outer circumferential surface of the pump shaft, the clearance is smaller than a penetration distance of a working medium in the first inner chamber, and the clearance is configured to prevent the working medium in the first inner chamber from entering the second inner chamber through the clearance.
 9. The electric oil pump according to claim 1, wherein the second rotor assembly is arranged between the first rotor assembly and the circuit board assembly; the first rotor assembly is arranged toward to one end of the pump shaft, the second rotor assembly is arranged close to another end of the pump shaft, the circuit board assembly is close to one end of the pump shaft mounted with the second rotor assembly; and one end of the pump shaft close to the first rotor assembly extends into the first inner chamber, and another end of the pump shaft close to the second rotor assembly extends into the second inner chamber.
 10. The electric oil pump according to claim 1, further comprising a partition plate, wherein the partition plate is provided in the second inner chamber, the electric oil pump further comprises a second support portion, the second support portion is integrally formed with the partition plate, the second support portion is arranged protruding from the partition plate toward the second inner chamber, the electric oil pump comprises a second bearing, and the pump shaft is directly supported on the second support portion, or the pump shaft is supported on the second support portion through the second bearing.
 11. The electric oil pump according to claim 10, wherein the partition plate comprises a third accommodating portion, the third accommodating portion is formed with at least part of a third accommodating cavity, and the third accommodating cavity is surrounded by at least part of an inner circumferential surface of the third accommodating portion, and the pump shaft passes through the third accommodating cavity, and at least part of the outer circumferential surface of the pump shaft is in a clearance fit with an inner circumferential surface of the third accommodating portion; or the electric oil pump comprises a second bearing, the second bearing is provided in the third accommodating cavity, the pump shaft passes through the second bearing, and an outer circumferential surface of the second bearing is in an interference fit with the inner circumferential surface of the third accommodating portion.
 12. The electric oil pump according to claim 1, wherein the first housing is detachably connected with the second housing through a first connection portion, the second housing is detachably connected with the third housing through a second connection portion, and the first connection portion and the second connection portion are not arranged in the first inner chamber or the second inner chamber.
 13. The electric oil pump according to claim 12, wherein the first connection portion comprises first screws, the first housing comprises a first flange portion, the first flange portion is arranged protruding from the first housing, the first flange portion is formed with first communication holes, the second housing is formed with first threaded holes, the first threaded holes are formed along a main body portion of the second housing, the first screws pass through the first communication holes and are mounted from a side close to the first housing, and the first screws are screwed to the second housing.
 14. The electric oil pump according to claim 1, wherein the electric oil pump comprises an outer sealing portion, the outer sealing portion comprises a first sealing ring and a second sealing ring which are sleeved on an outer circumferential surface of the second housing, the first sealing ring is arranged close to the first housing, and the second sealing ring is arranged close to the third housing.
 15. The electric oil pump according to claim 14, wherein the first rotor assembly comprises a first rotor and a second rotor, a hydraulic chamber with a variable volume is formed between the first rotor and the second rotor, the electric oil pump further comprises a first flow port and a second flow port, the working medium flows into the electric oil pump through the first flow port, and the working medium flows out of the electric oil pump through the second flow port; and the electric oil pump further comprises a first communication cavity and a second communication cavity, the first communication cavity is arranged between the first flow port and the hydraulic chamber, the first communication cavity is in communication with the first flow port, the second communication cavity is arranged between the second flow port and the hydraulic chamber, and the second communication cavity is in communication with the second flow port.
 16. The electric oil pump according to claim 2, wherein the partition portion comprises a first support portion, the first support portion is arranged protruding from a main body portion of the partition portion toward the second inner chamber, and the pump shaft is directly or indirectly supported on the first support portion.
 17. The electric oil pump according to claim 3, wherein the partition portion comprises a first support portion, the first support portion is arranged protruding from a main body portion of the partition portion toward the second inner chamber, and the pump shaft is directly or indirectly supported on the first support portion.
 18. The electric oil pump according to claim 4, wherein the partition portion comprises a first support portion, the first support portion is arranged protruding from a main body portion of the partition portion toward the second inner chamber, and the pump shaft is directly or indirectly supported on the first support portion. 